Hey guys, I just got my 6.0 swap done, and I had a question about preignition. I hadn't tuned it yet, I was driving it around to get some data for my tune and it was running pretty lean (I found out afterwards, no wideband, but fuel trims were HIGH, 10-30 ). Anywho, I felt/heard 2 loud 'knocks' while climbing a shallow hill, almost like the engine slammed into the frame rail, accompanied by a brief lack of power, so I let off the gas and start pulling over, but it smooths out so I turn around and head home (about 30 seconds down the road) and immediately add fuel to the VE table. It seems to run okay now(smooth, no rod/bearing noises, plenty of power), so my question is what does it sound like I experienced and is there a risk I screwed something up?

 

Also sorry for the possibly misleading title, but preignition is my best guess at what happened, although I thought that usually meant more or less instant failure

 

That's not what you heard. Detonation sounds like a handful of bb's being rolled around in an empty pop can.

 

I know what detonation sounds like, but I was under the impression that detonation and preignition were different things with different indicators. So does it sound like that was an external noise? like my engine actually hitting something under the hood?

 

You likely heard the engine pop or backfire, which is very common on an untuned engine. That pop through the intake sounds just like what you are describing. Do not drive the car again until you have a tuner sitting in the passenger seat with his laptop connected. You will likely hurt this engine if you continue to run it as is.

 

any suggestions on what I should be adjusting in the tune to stop it from backfiring? I'd prefer to have a tuner come to me, but I don't have many local, and I'm not sure if they do 'home visits' so there's a real possibility I might have to drive to them

 

And on average, what should I expect to pay for a full tune? I had one shop quote me $500 but being that this is uncharted territory for me; I have no idea if that's a good price or on the high side

 

That sounds like a reasonable price for a dyno tune.

 

A lot of tuners can give you a 'base' tune that will get the car running safely. Most tuners have some sort of standalone harness they can hook your PCM to and tune in their shop without the computer there. It won't be a perfect tune, and WOT is out of the question, but like I said, the car will be driveable, and will do so (mostly) safely. Certainly won't have any backfiring issues like you are now.

 

500$ is what everyone charges around me. Most of them will give you a base tune so you can try to them and get a dyno tune. Again this is basically just so you can baby her there.